Severe Emilee, Surridge Ben W J, Fiener Peter, Coogan Michael P, Platel Rachel H, James Mike R, Quinton John
Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, U.K.
Institute of Geography, University of Augsburg, Alter Postweg 118, Augsburg 86159, Germany.
Environ Sci Technol. 2025 Jul 15;59(27):14063-14074. doi: 10.1021/acs.est.5c04795. Epub 2025 Jul 2.
Erosion is hypothesized to be a significant process transporting microplastics (MPs) from soils to aquatic environments, however, the factors controlling this process are poorly understood. Using a novel combination of high-frequency photography and fluorescent particles, we compared the transport of three MPs to that of a sand particle during rainfall simulations: linear low-density polyethylene (LLDPE), polystyrene (PS), and poly(methyl methacrylate) (PMMA). We measured the "real time" movement of particles on the soil surface alongside the number of particles transported through splash erosion and surface runoff. Our results show that MPs of all polymer types demonstrated more rapid transport from the soil surface compared to sand particles throughout the rainfall simulations. Prior to surface runoff, ∼65-75% of MPs and sand particles were removed from the soil surface through raindrop-driven incorporation into the soil matrix. Surface runoff and splash erosion accounted for the transport of approximately 47% of PMMA and 57% of PS, while only 30% of sand particles were mobilized by these processes. This research establishes a benchmark for evaluating MP mobility to current knowledge of soil particle movement, which is critical for estimating the redistribution of MPs within soils and their ultimate flux to aquatic ecosystems.
侵蚀被认为是将微塑料（MPs）从土壤输送到水生环境的一个重要过程，然而，控制这一过程的因素却鲜为人知。我们使用高频摄影和荧光颗粒的新颖组合，在降雨模拟过程中比较了三种微塑料与沙粒的输运情况：线性低密度聚乙烯（LLDPE）、聚苯乙烯（PS）和聚甲基丙烯酸甲酯（PMMA）。我们测量了土壤表面颗粒的“实时”移动情况以及通过溅蚀和地表径流输送的颗粒数量。我们的结果表明，在整个降雨模拟过程中，所有聚合物类型的微塑料从土壤表面的输运速度都比沙粒快。在地表径流之前，约65%-75%的微塑料和沙粒通过雨滴驱动混入土壤基质而从土壤表面被去除。地表径流和溅蚀分别导致约47%的PMMA和57%的PS被输运，而这些过程仅使30%的沙粒发生移动。这项研究为根据当前土壤颗粒移动知识评估微塑料迁移率建立了一个基准，这对于估计微塑料在土壤中的再分布及其向水生生态系统的最终通量至关重要。
